Electric underfloor heating and wet type?

[rekab6969]

Hi Guys,

Looking to run wet type underfloor heating is the concrete slab of a log cabin build, would also like to have electric above it in a latex screed, is this allowed?

Thanks,

db.

 

[ericmark]

Seen nothing saying not allowed, the main thing about under floor heating is ensuring it does not over heat, 27°C is normally the limit for floor temperature, with wet the water temperature is controlled, with electric there are two common methods, one is a sensor in the floor, the other is special chemical heating tape (RayChem) which changes resistance as it heats up, the former can have hot spot issues where some thing is placed on the floor, the RayChem is claimed not to have that problem.

Clearly using two one must ensure if both are used this can't cause over heating, I know with the one I laid there was too tight of a bend in the pocket and when the sensor failed it could not be replaced, and the sensor wires can't easy be extended so there are some logistic problems to ensure it can be maintained, I would have thought it would be too much of a problem ensuring correct control, and having electric and water seems pointless.

 

[Taylortwocities]

Hi Guys,

Looking to run wet type underfloor heating is the concrete slab of a log cabin build, would also like to have electric above it in a latex screed, is this allowed?

Thanks,

db.

Like ericmark, your post seems to indicate that you are planning to have

wet type underfloor heating

and then electric underfloor heating on top. Surely you don't mean that? Or do you?
Can you clarify.

 

[rekab6969]

Thanks fir your replies.

I’ve installed wet type underfloor which was laid on top of kingspan then a 50mm screed laid on top. The whole screed heats up slowly to maintain a constant heat and it modulates by being on for long periods, this is fine in a constantly occupied house.

My cabin will not be constantly occupied, sometime it will be for long periods, sometimes a few hours.

So I was thinking electric would be a bonus for times when it was used for the shorter periods.

regards installation, as mentioned the wet pipes go in the slab / screed. the electric in a thin latex screed just below any floor covering.

Cheers,

db.

 

[SimonH2]

Unless you have insulation between the slab and the upper layer with the lecky UFH in, then the lecky UFH will still heat the whole slab. Obviously such insulation would stop the wet UFH from working
If properly designed, the wet UFH should be capable of heating up more quickly than electric will - unless you put in an excessively high powered lecky system, which would be dangerous if controls weren't well designed and maintained.
Another option would be to have the UFH for "foot comfort" and longer use, with another source (e.g. a wet fan-coil blower) for rapid heat up for shorter use.

 

[rekab6969]

Ahhhh. Yes. Thank you. That makes perfect sense, obvious once pointed out.

I’ll go with the wet underfloor now.

Thank you.

db.